IVIC Syndrome

Hereditary polymalformative syndrome characterized by hearing impairment, radial ray defects and hand anomalies, internal ophthalmoplegia, thrombocytopenia, and leukocytosis.

Arias Syndrome; Oculo-Oto-Radial Syndrome (OO-RS).

IVIC is an acronym that stands for Instituto Venezolano de Investiaciones Cientifícas, where Sergio Arias Cazorla, a Venezuela geneticist, worked.

This syndrome was observed in 19 living descendants of a Caucasoid family that migrated to Venezuela from the Canary Islands in the early 1800s.

Autosomal dominant with complete penetrance and widely variable expression. Investigation on monozygotic twins indicated that modification of OORS gene expression must be environmental or epigenetic rather than genetic. It may represent an “iceberg dominant” trait because of the wide range of severity.

The gene responsible for this syndrome has variable expressivity, with the most consistent manifestation being a developmental defect of the upper limbs. A mesenchymally based defect could be implicated in the pathogenesis.

The radial ray is consistently involved, with degrees of severity ranging from an almost normal thumb to a hypoplastic, triphalangeal thumb attached to the radial border of the second digit. Long and slender metacarpal bones and hypoplastic carpal bones may coexist with proximally fused ulna and radius. One patient had a single forearm bone. Other findings include hearing loss (very frequent), extraocular muscle involvement in the form of strabismus (frequent), mild thrombocytopenia and leukocytosis (less frequent), and imperforated anus (10% of patients). Although very rare, incomplete right bundle branch block has been reported in both children and adults. Clinical examination, upper limb radiographs, audiograms, ophthalmologic examination, and blood cell count contribute to the diagnosis.

Obtain blood cell count: possibility of mild thrombocytopenia and/or leukocytosis. Obtain an electrocardiogram (ECG): rare reported cases of incomplete right bundle branch block with occasionally increased QT interval were not associated with any significant cardiovascular dysfunction.

If present, thrombocytopenia is mild and usually does not necessitate platelet transfusion. Nonetheless, if locoregional anesthesia is considered, an adequate platelet level should be obtained before proceeding. The rare cardiac manifestations in the form of ECG changes mentioned under Precautions Before Anesthesia have been described as “benign and single cardiac sign” by the authorities on OORS.

No known implications with this condition.

Holt-Oram Syndrome: Autosomal dominant polymalformative syndrome caused by defective development embryonic development of the radial ray associated with cardiac malformation (atrial septal defect). Mapped to band 12q24.1 (gene encoding the human transcription factor TBX5).

TAR Syndrome (Thrombocytopenia and Absent Radius): Autosomal recessive syndrome characterized by thrombocytopenia with potentially severe bleeding episodes, primarily during infancy, aplasia of the radius (the ulna is often involved, too), and various malformations (heart, kidneys).